Investigation of transonic bi-convex corner flows

Experiments were performed to investigate a transonic, turbulent boundary layer over a bi-convex corner. The total turning angle η   ranged from 10 deg to 17 deg. In subsonic expansion flows, the presence of a bi-convex corner results in a decrease in local peak Mach number MpeakMpeak and the amplitude of peak surface pressure fluctuations (σp/pw)max(σp/pw)max. There is a delay in transition from subsonic to transonic expansion flows. A dual expansion is observed in transonic expansion flows. Shock structure, boundary-layer separation and (σp/pw)max(σp/pw)max were dependent on freestream Mach number M  , first turning angle η1η1 and η  . The length of the first corner L1L1 also plays an important role. An increase in L1L1 results in less flow expansion, while a decrease in the amplitude of (σp/pw)max(σp/pw)max is associated with a shorter L1L1.